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What is the travel of your current focuser from fully racked in to fully racked out? If less than 35mm then a 35mm extension tube may be too long but it depends on where your focal plane sits. Also different eyepieces have different field stop positions so some may come to focus and some not.
Have you determined the focal plane? To do this get a piece of tracing paper and place flat over focuser (no eyepiece). Point at the Moon (at night) and try and focus onto the paper. It will be at focus at the focal plane. If this is above the fully racked out focuser then measure the distance. If Moon not up focus on a distant object on the horizon during the daytime. Contrast will be low so very translucent almost transparent paper is better during the daytime or put a hood over your head and focal plane (think old photographers).
There are many variables and a 35mm 2” diameter extension may work but if too long then a radius plate like I suggested is the go. However try adjusting the collimation bolts first and/or get an extension tube. Tighten each collimation bolt evenly to bring the focal plane inward. You will have to re-collimate.
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